754 



MALLOPHAGA AND ANOPLURA [LICE) 



The alimentary canal consists of a mouth followed by a chitinous pharyngeal 

 pump, into which the ducts of the salivary glands open, and an oesophagus 

 which leads into the mid-gut. This second part of the canal consists of two 

 portions, of which the first appears to be a crop and the second a chylific 

 ventricle. There are four Malpighian tubules. The intestine shows no differ- 

 entiation into small and large. The rectum is globular, with a distended 

 posterior portion containing the rectal papillae. The fat-body is well developed. 

 The female generative organs consist of two ovaries with oviducts. Each 

 ovary consists of five to six follicular tubes. The two oviducts unite into a 

 common duct, and there is a spermatheca. The male organs are testes, 

 vasa deferentia, vesiculae seminales, and penis. 



Life-History. — The ova, which are attached to the hairs of the host, give rise 



larvae, which closely resemble the adults. 



Fig. 



366. — Pediculus humanus 

 L.: Male, (x 25.) 



Fig. 367. — Pediculus humanus 

 L. : Female, (x 25.) 



Pathogenicity —Lice are imporLant carriers of disease, being 

 vectors in certain forms of relapsing fever, in typhus, and in trench 

 fever, etc. 



Classification. — The Pediculidse are subdivided into two sub- 

 families, which may be recognized as follows : — 



A. Pediculidce with five-jointed antennae — PediculincB. 



B. PedimlidcB with three-jointed antennae — Pedicince. 



Subfamily A: PediculinvE Enderlein, 1904. 



Definition.— Pediculid^ with five-jointed antennae. 

 Classification, — The Pediculinae contain two genera, both of which 

 are parasitic on man, and which may be differentiated as follows:- — 



{a) All legs strong, distinct neck, thorax narrower than 



abdomen — Pediculus. 

 (b) Forelegs long, slender, with three claws; no neck; 



thorax broader than abdomen — Phthirius. 



